Process of producing ferro-silicon of high silicon content in blast-furnaces.



ll FATE zrosnrn n. aonnson', an, or HARTSDALE, new YORK.

Li h u PROCESS OF PRODUCING FERRO-SILICON OF HiIGI-I SILIGON CONTENT INBLAST- FURNACES.

No LQrawing.

To all whom it may concern:

Be it known that l, Josnrn E. JOHNSON, J12, a citizen of the UnitedStates, residing at Hartsdale, in the county of lVestchester and Stateof New York, have invented certain new and useful Improvements inProcesses of ProducingFerro- Silicon of High Silicon Content inBlast-Furnaces, of which the following is a specification.

This invention relates to a process of smelting ores in the blastfurnace, and aims to produce in an economical manner, ferrosiliconcontaining a high percentage of silicon.

,There are at present in common use two varieties of commercialvir'erro-silicon, one produced in the blast furnace, and the otherproduced in the electric furnace. variety, while comparativelyinexpensive to The first produce, is low in its percentage of silicon,'

and the second variety while very high in silicon content, commonly 50%or more, is expensive to produce on account of the high electric currentconsumption.

It is the object of my invention to produce in the blast furnace,ferro-silicon containing a high percentage of silicon, thereby securingthe advantage of the electric furnace in respect to the high siliconcontent, and the advantage of the blast furnace with respect to economyof production.

With this object in View, my invention consists of an improved method ofsmelting, in which a blast is employed rich in oxygen, whereby thetemperature of combustion is increased to such degree that the silicawill be reduced on a scale which will produce ferro-silicon containing ahigh percentage of silicon and equahng the product commonly produced inthe electric furnace.

In carrying my improred method into ellect. I make use of a form ofblast furnacc, in a general way similar to that now 1l11l"1:5l\llemployed for smelting ores, and I charge the sam with ore and fuelin-the usual and well known manner. 1 introduce at the base of thecharge, through the usual twyers, a blast which is rich in oxygen ascompared with the usual blast of atmospheric air. the resultof which 1sthe production of a much higher combustion temperature than is availablein the furnace as ordinarily operated, and a correspondtion.

vto be incorporated.

Specification of Letters Patent. Pafhgnfiafi June 26, 1-917 Applicationfiled June 20, 1916. Serial NO. 104,779.

ingly increased reduction of the silica. The reactions 1n this operationmay be expressed by the following formula:

S10 +20 xFeZiFe Si 2C0.

Where atmospheric air is employed in the blast there is about 3; tlmesmore by weight of nitrogen than there is of oxygen, and

- since, other things being equal, the temperaas a dead weight on thecombustion and keeps the temperature down to such point that thereduction of silica is confined to limits in which the final productcontains a comparatively small per cent. of silicon, rarely above 16%.

By my invention, by employing a blast rich in oxygen the increasedtemperature of combustion is Very marked, and if pure oxygen wereemployed the gain would be so enormous that it would greatly exceed therequirements for the end in View, and since .the increase of temperatureneed be only about higher than is now obtainable with the use ofatmospheric air, I find 1t sullicient for my purpose to employ a blastin which the oxygen and nitrogen will boot equal.

weights, or in approximately that propor- A mixture of this character ismore economically produced commercially than pure oxygen, andsuch'mixture is sul'licicntly 'rich in oxygen to obtain the temperaturerequired, for the reduction of the silica on the deslred mcreased scale,and for the crcation of the amount of heat available at that temperatureto bring about such reduction.

Ferro-silicon .as most generally employed in metallurgy,contains aboutequal proportions of iron and silicon in order to enable it to combineunder the most favorable conditions with the molten metal in which it isA blast in which the nitrogenand oxygen are mixed inequal orsubstantially equal proportions I have found admirably adapted forproducing that temperature of combustion which will bring about thereduction of the silica and iron in the proportions mentioned. and ablast mixture of this character may be economically andconve'i'iientlyproduced and with a far smaller plant than is requiredfor a richer mixture or for pure oxygen.

nace, which-consists in chargingthe furnace with ore and fuel, andsupplying a blast rch in oxygen to reduce the slhcaon ascale-topro'cluce, ferrosilicon containing a high percentage of silicon.r

2. The process of producing ferro-silicon of substantially 50% siliconin a blast furn ace, which consists in charging the furnace with ore andfuel, and supplying a blast containing equal" or substantially equalparts by weight of oxygen and nitrogen to reduce the silica on a scaletoproduce a ferro-silicon containinga high percentage .of silica.--

In testimony Whereof, I have affixed my signature. 7 r.

' JOSEPH E. JOHNSON; JR.

